Why does changing one array alters the other?

Question

Consider this tiny bit of javascript code:

var a = [1, 2, 3],
    b = a;

b[1] = 3;

a; // a === [1, 3, 3] wtf!?

Why does \"a\" change when

Answer 1

the statement x = y is the only special one here, it means "point the variable x at the object y.

Pretty much every other operation is an operation which changes the object referred to by x

b = a;
b[1] = 3;

So, your first statement points the variable b at the array also referred to as a

Your second statement alters the array pointed to by b (and also by a)